To ensure the effectiveness of network policies of virtual machines in infrastructure as a service (IaaS ) environments which adopted the virtual ethernet bridge ( VEB ) model,a policy dynamic loading mechanism for virtual network interface (VIF) of virtual machine at runtime was studied.Through decoupling the network policy information from virtual machine native configure file,analyzing the factors of impacting the effectiveness of VIF’s policy and defining the essential factors of loading VIF’s policy,a mechanism was proposed to load the policy to right place at the appropriate time point to ensure the effectiveness of network policies in total life cycle of virtual machine.The results showed that the VIF’s policy could be loaded completely in milliseconds and the policy lacking period was eliminated,and based on the independent character of network policies,the policies on-demand extension and dynamic change for virtual machine at runtime were supported.
